1. Field of the Invention
This invention relates to striking hammers used in pianos to strike the strings of the piano. It is particularly concerned with providing means for exactly positioning the hammer head on a shank so that when the hammer head is mounted on the action rail in the piano, the exact striking point of the hammer head will contact the string at its critical node, and insure that each hammer head will rise to strike its strings and do so without any side-to-side movement or scooping motion.
2. Prior Art
It has long been recognized that it has been necessary to be able to replace striking hammer heads of a piano's and to have the replacement hammer heads perform in the same manner as the original hammer heads after their installation on the action's flange rail and placed back in the piano for operation. The installed hammer heads wear and occasionally break; and if piano quality is to be maintained, the replacement hammer heads must be properly aligned and fitted on their shanks so that the striking points thereof will properly engage the strings of the piano at their critical nodes and at predetermined angles with reference to the X, Y, and Z coordinate axes. The axis of rotation must always be parallel the flange rail.
In replacing the striking hammer heads, it has been common in the past to utilize the old hammer heads being replaced as guides, to visually set the replacement hammer heads in respect to their shanks so as to provide replacement hammer heads having the same pitch, side angle and travel accuracy of the hammer heads being replaced. This has generally been done through trial and observation techniques and visual judgment, as is more fully explained in the articles entitled "Grand Hammer Hanging", by Cliff Geers beginning at page 12 of the May, 1984, Piano Technician's Journal, and "Traveling Hammers", by Jack Krefting, beginning on page 11 of the March, 1985, issue of the Piano Technician's Journal.